A Dinitrosyliron Complex within the Homoleptic Fe(NO)₄ Anion: NO as Nitroxyl and Nitrosyl Ligands within a Single Structure

Nitrosylation of the chelate–thiolate-containing dinitrosyliron complex (DNIC) [(S­(CH2)3S)­Fe­(NO)2]− triggers nitric oxide (NO) activation to generate the homoleptic nitrosyl {Fe­(NO)2}9 DNIC [Fe­(NO)4]− (1) made up of two nitroxyls (or two NO anions) attached to a delocalized {Fe­(NO)2}9 motif. The significantly longer N3–O3/N4–O4 [1.380(12) and 1.280(12) Å] and Fe1–N3/Fe1–N4 [2.008(11) and 2.045(10) Ǻ] bond distances reflect that N3–O3 and N4–O4 of complex 1 may act as the nitroxyl-coordinated ligands. That is, the electronic structure of the DNIC 1 is best described as a {Fe­(NO)2}9 motif coordinated by two nitroxyl (NO–) ligands.